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SECTION 23 81 43
AIR-SOURCE UNITARY HEAT PUMPS
SPEC WRITER NOTES:
1. Delete between //______// if not
applicable to project. Also delete any
other item or paragraph not applicable
in the section and renumber the
paragraphs.
PART 1 - GENERAL
1.1 DESCRIPTION
A. This Section specifies electrically operated air-source unitary heat
pumps.
B. Definitions:
1. Coefficient of Performance (COP) - Cooling: The ratio of the rate of
heat removed to the rate of energy input in consistent units, for a
complete refrigerating system or some specific portion of that system
under designated operating conditions.
2. Coefficient of Performance (COP) - Heating: The ratio of the rate of
heat delivered to the rate of energy input is consistent units for a
complete heat pump system, including the compressor and, if
applicable, auxiliary heat under designated operating conditions.
3. Energy Efficiency Ratio (EER): The ratio of net cooling capacity is
Btu/h to total rate of electricity input in watts under designated
operating conditions.
4. Heating Seasonal Performance Factor (HSPF) - Total heating output of
heat pump during its normal annual usage period for heating in Btu/h
divided by total electric energy input in watts during the same
period.
5. Seasonal Energy Efficiency Ratio (SEER) - Total cooling output of an
air conditioner during its normal annual usage period for cooling in
Btu/h divided by total electric energy input in watts during the same
period.
6. Air-Source Unitary Heat Pump: One or more factory made assemblies
that normally include an indoor conditioning coil, compressor(s) and
an outdoor refrigerant-to-air coil. These units provide both heating
and cooling functions.
1.2 RELATED WORK
A. Section 01 00 00, GENERAL REQUIREMENTS: For pre-test requirements.
//B. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL
COMPONENTS: Seismic requirements for non-structural equipment.//
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C. Section 23 05 11, COMMON WORK RESULTS FOR HVAC: General mechanical
requirements and items, which are common to more than one section of
Division 23.
D. Section 23 23 00, REFRIGERANT PIPING: Requirements for field refrigerant
piping.
E. Section 23 31 00, HVAC DUCTS AND CASINGS: Requirements for sheet metal
ductwork.
F. Section 23 09 23, DIRECT-DIGITAL CONTROL SYSTEM FOR HVAC: Requirements
for controls and instrumentation.
G. Section 23 05 93, TESTING, ADJUSTING, AND BALANCING FOR HVAC:
Requirements for testing, adjusting and balancing of HVAC system.
H. Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS: Requirements for
commissioning, systems readiness checklists, and training.
I. Section 01 91 00 – GENERAL COMMISSIONING REQUIREMENTS
1.3 QUALITY ASSURANCE:
A. Refer to specification Section 23 05 11, COMMON WORK RESULTS FOR HVAC
B. Comply with ASHRAE Standard 15, Safety Code for Mechanical
Refrigeration.
C. Comply with ASHRAE Standard 90.1-2010, Energy Standard for Buildings
except Low-Rise Residential Buildings for cooling and heating
performance requirements when tested in accordance with AHRI
//210/240//AHRI 340/360// and UL 1995.
D. Heating Performance shall conform to ASHRAE requirements when tested in
accordance with AHRI //210/240//AHRI 340/360// and UL 1995.
//E. Comply with requirements in Section 13 05 41, SEISMIC RESTRAINT
REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS.//
1.4 SUBMITTALS
A. Submit in accordance with specification Section 01 33 23, SHOP DRAWINGS,
PRODUCT DATA, and SAMPLES.
B. Manufacturer’s Literature and Data.
1. Air-Source Unitary Heat pump:
a. Packaged units
b. Split system
C. Certification: Submit, simultaneously with shop drawings, a proof of
certification that this product has been certified by AHRI.
D. Performance Rating: Submit catalog selection data showing equipment
ratings and compliance with required cooling and heating capacities EER
and COP values as applicable.
E. Completed System Readiness Checklists provided by the Commissioning
Agent and completed by the contractor, signed by a qualified technician
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and dated on the date of completion, in accordance with the requirements
of Section 23 08 00 COMMISSIONING OF HVAC SYSTEMS.
1.5 APPLICABLE PUBLICATIONS:
A. The publications listed below form a part of this specification to the
extent referenced. The publications are referenced in the text by the
basic designation only.
B. Federal Specification (Fed. Spec.):
A-A-50502-90 ........... Air-conditioner (UNITARY HEAT PUMP), AIR TO AIR
(3000 TO 300,000 BTUH)
C. Air-Conditioning Heating and Refrigeration Institute (AHRI) Standards:
AHRI-DCPP .............. Directory of Certified Product Performance Applied Directory of Certified Products
210/240-08 ............. Performance Rating of Unitary Air-Conditioning
and Air-Source Heat Pump Equipment
270-08 ................. Sound Rating of Outdoor Unitary Equipment
310/380-04 ............. Standard for Packaged Terminal Air-Conditioners
and Heat Pumps (CSA-C744-04)
340/360-07 ............. Commercial and Industrial Unitary AirConditioning and Heat Pump Equipment
D. Air Movement and Control Association (AMCA):
210-07 ................. Laboratory Methods of Testing Fans for
Aerodynamic Performance Rating (ANSI)
410-96 ................. Recommended Safety Practices for Users and
Installers of Industrial and Commercial Fans
E. American National Standards Institute (ANSI):
S12.51-02 (R2007) ...... Acoustics - Determination of Sound Power Levels
of Noise Sources Using Sound Pressure Precision Method for Reverberation Rooms (same
as ISO 3741:1999)
F. American Society of Heating, Refrigerating and Air-Conditioning
Engineers Inc (ASHRAE):
15-10 .................. Safety Standard for Refrigeration Systems (ANSI)
62.1-10 ................ Ventilation for Acceptable Indoor Air Quality
(ANSI)
90.1-07 ................ Energy Standard for Buildings except Low-Rise
Residential Buildings
2008 Handbook .......... HVAC Systems and Equipment
G. American Society of Testing and Materials (ASTM):
B117-09 ................ Standard Practice for Operating Salt Spray (Fog)
Apparatus
H. National Electrical Manufacturer’s Association (NEMA):
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MG 1-09 (R2010) ........ Motors and Generators (ANSI)
ICS 1-00 (R2005) ....... Industrial Controls and Systems: General
Requirements
I. National Fire Protection Association (NFPA):
90A-09 ................. Standard for the Installation of AirConditioning and Ventilating Systems
J. Underwriters Laboratory (UL):
1995-05 ................ Heating and Cooling Equipment
PART II- PRODUCTS
2.1 UNITARY HEAT PUMPS, AIR TO AIR
A. Units shall comply with Fed Spec A-A-50502//Type I, having factory
assembled refrigerant circuit or circuits (Packaged Unit), // Type II,
(Split System) having remote outdoor section separate from indoor
Section,// Class 1, "Department of Energy" (DOE) covered products (units
with cooling capacity up to 65000 Btu/hr// Class 2, Non–DOE covered
products (units with cooling capacity up to 300,000 Btu/hr //.
1. Unitary heat pumps shall bear the United States Environmental
Protection Agency, Energy Star label and shall have a minimum Heating
Season Performance Factor (HSPF) of //8 (Type I – Packaged
Unit),//8.2 (Type II – Split System),// and a minimum Seasonal Energy
Efficiency Ratio (SEER) of //14 (Type I – Packaged Unit),//14.5 (Type
II – Split System)//.
B. Applicable AHRI Standards: Units shall be listed in the corresponding
ARI Directory of Certified products shown in paragraph, APPLICABLE
PUBLICATIONS:
1. Air Source Unitary heat pumps with capacity less than 19 KW (65,000
Btu/hr), Comply with AHRI 210/240.
2. Air Source heat pump with capacity above 19KW (above 65,000 Btu/hr,
Comply with AHRI 340/360.
C. Casing: Unit shall be constructed of zinc coated, //heavy-gage // 14gage minimum // galvanized steel. Exterior surfaces shall be cleaned,
phosphatized, and finished with a weather-resistant baked enamel finish.
Unit surfaces shall be tested 500 hours in a salt spray test in
compliance with ASTM B117. Cabinet panels shall have lifting handles and
shall be water- and air-tight seal. All exposed vertical, top covers and
base pan shall be insulated with // 13-mm (1/2–inch) // 25-mm (1-inch)
// 50-mm (2-inch) // matt-faced, fire-resistant, odorless, glass fiber
material. Surfaces in contact with the airstream shall comply with
requirements in ASHRAE 62.1-2010.
The base of the unit shall have
provisions for forklift and crane lifting.
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D. Filters: One inch, MERV 7, throwaway filter shall be standard on all
units below 19kW (6 Tons). Filter rack can be converted to two inch
capability. Two inch, MERV 8, throwaway filters shall be factory
supplied on all units above 19 kW (6 Tons).
E. Compressors: Compressors shall be direct-drive, hermetic scroll type
with centrifugal type oil pumps. Motor shall be suction gas-cooled.
Internal overloads and crankcase heaters shall be utilized with all
compressors.
F. Refrigerant Circuit: A minimum of two circuits is required. Each
refrigerant circuit shall have independent fixed orifice or thermostatic
expansion devices, service pressure ports, and refrigerant line filter
driers factory installed as standard. An area shall be provided for
replacement suction line driers.
DESIGNER’S NOTE: For high-humidity
locations (VA HVAC Design Manual), provide
E-coated aluminum fins and corrosionresistant cabinets. See Paragraph N below
G. Evaporator and Condenser Coils: Internally finned, DN 10 (NPS 3/8)
copper tubes mechanically bonded to a configured aluminum plate fin
shall be standard. The evaporated coil and condenser coil shall be leak
tested at the factory to 1378 kPa (200 psig) and pressure tested to 2756
kPa (400 psig).
evaporator coils.
All dual compressor units shall have intermingled
Sloped condensate drain pans shall be provided.
H. Outdoor fans: Direct driven, statically and dynamically balanced, drawthrough in the vertical discharge position. The fan motors shall be
permanently lubricated and shall have built-in thermal overload
protection.
I. Indoor Fan:
//1. Forward-Curved, Centrifugal Fan: Provide V-belt driven with
adjustable motor sheaves //adjustable idler-arm assembly for quickadjustment of fan belts and motor sheaves//. Motors shall be
thermally protected. Provide oversized motors for high static
application. Motors shall meet the U.S. Energy Policy Act of 2005
(EPACT).//
//2. Plenum Fans // Provide direct-drive, Arrangement 4, plenum fan(s)
equipped with variable-speed drives.
Maximum fans in an array shall
not exceed four.//
J. Defrost Controls: A time initiated, temperature terminated defrost
system shall ship with a setting of 70-minute cycle, with a choice of
50- or 90-minute cycle. Timed override limits defrost cycle to 10
minutes shall be available on units from 35- to 70-kW (10 to 20 tons).
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Adaptive demand defrost shall be provided on units below 35 kW (10
Tons).
K. Unit Electrical
1. Provide single point unit power connection.
2. Unit control box shall be located within the unit and shall contain
controls for compressor, reversing valve and fan motor operation and
shall have a 50 VA 24-volt control circuit transformer and a terminal
block for low voltage field wiring connections.
3. Safety Controls - High pressure, low temperature, and low pressure
safety switches shall be wired through a latching lockout circuit to
hold the conditioner off until it is reset electrically be
interrupting the power supply to the conditioner.
All safety
switches shall be normally closed, opening upon fault detection.
DESIGNER’S NOTE: Select one of the two
control configurations (stand-alone
electric or DDC)
L. Operating Controls
1. Provide unit with //low voltage electric controls//factory supplied
DDC control system.//
//2. Low voltage, adjustable room thermostat to control heating and
cooling in sequence with delay between stages, compressor and supply
fan to maintain temperature setting. Include system selector
switch//(heat-off-cool)//(off-heat-auto-cool)//and fan control switch
(auto-on)//.
//3. Unit DDC Controller:
a. Unit controller shall include input, output and self-contained
programming as needed for complete control of unit.
b. Unit controller shall be BAC net compliant and utilize BAC net
operating protocol.
c. Control system shall seamlessly interface with temperature control
system as specified in Section 23 09 23, DIRECT DIGITAL CONTROL
SYSTEMS FOR HVAC without requiring gateways or any other interface
devices.
d. All program sequences shall be stored on board in EEPROM.
batteries shall be needed to retain logic program.
No
All program
sequences shall be execut4ed by controller 10 times per second and
shall be capable of multiple PID loops for control of multiple
devices.
Programming of logic controller shall be completely
modifiable in the field over installed BACnet LANs.
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e. Temperature Control System Interface:
Points shall be available
from the unit controller for service access and display and/or
control.
f. Space Temperature Sensor: The wall mounted sensor shall include
occupied and unoccupied setpoint control, pushbutton unoccupied
override, space temperature offset and space temperature
indication. Refer to Section 23 09 23, DIRECT DIGITAL CONTROL
SYSTEM FOR HVAC for additional requirements.
M. Accessories:
1. Electric Heater: Constructed of heavy-duty nickel chromium elements.
Staging shall be achieved through the unit control processor. Each
heater shall have automatically reset high limit control. Heaters
shall be individually fused from the factory and shall comply with
NEC and CEC requirements. Power assemblies shall provide single point
connection. Electric heat modules shall be listed and labeled by a
national recognized testing laboratory acceptable to authorities
having jurisdiction. Electric heater controls shall confirm the
supply fan is operating before electric elements are energized.
Operate electric heater in //2//3// stages when outdoor ambient is
too low to maintain space thermostat setting with compressor
operation.
2. Economizer: // Down flow // Horizontal flow//;// field // factory //
installed; and shall include fully modulating 0-100 percent motor and
dampers, barometric relief, minimum position setting and fixed dry
bulb.// Solid state enthalpy and differential enthalpy control shall
be field-installed //.
3. Oversized Motors: // Factory // Field // installed over sized motor
shall be available for high-static application.
2.2 CORROSION PROTECTION
A. Remote Outdoor Condenser Coils:
1. Epoxy Immersion Coating – Electrically Deposited: The multi-stage
corrosion-resistant coating application comprises of cleaning (heated
alkaline immersion bath) and reverse-osmosis immersion rinse prior to
the start of the coating process.
The coating thickness shall be
maintained between 0.6-mil and 1.2-mil.
Before the coils are
subjected to high-temperature oven cure, they are treated to permeate
immersion rinse and spray.
Where the coils are subject to UV
exposure, UV protection spray treatment comprising of UV-resistant
urethane mastic topcoat shall be applied.
Provide complete coating
process traceability for each coil and minimum five years of limited
warranty.
The coating process shall be such that uniform coating
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thickness is maintained at the fin edges.
The quality control shall
be maintained by ensuring compliance to the applicable ASTM Standards
for the following:
a. Salt Spray Resistance (Minimum 6,000 Hours)
b. Humidity Resistance (Minimum 1,000 Hours)
c. Water Immersion (Minimum 260 Hours)
d. Cross-Hatch Adhesion (Minimum 4B-5B Rating)
e. Impact Resistance (Up to 160 Inch/Pound)
B. Exposed Outdoor Cabinet:
1. Casing Surfaces (Exterior and Interior): All exposed and accessible
metal surfaces shall be protected with a water-reducible acrylic with
stainless steel pigment spray-applied over the manufacturer’s
standard finish.
The spray coating thickness shall be 2-4 mils and
provide minimum salt-spray resistance of 1,000 hours (ASTM B117) AND
500 hours UV resistance (ASTM D4587).
PART 3- EXECUTION
3.1 INSTALLATION
A. Install heat pumps according to manufacturers printed instructions.
B. Install electrical and control devices furnished by the manufacturer but
not specified to be factory mounted. All electrical work shall comply
with Division 26 Sections.
C. Ductwork: Comply with requirements in Section 23 31 00, HVAC DUCTS AND
CASINGS.
D. Piping:
Comply with requirements in Section 23 23 00, REFRIGERANT
PIPING.
3.2 STARTUP AND TESTING:
A. Perform startup checks according to manufacturer’s written instructions.
B. Test controls and demonstrate its compliance with project requirements.
Replace damaged or malfunctioning controls and equipment and retest the
equipment to the satisfaction of the Resident Engineer.
C. Furnish test reports to the Senior Resident Engineer in accordance with
specification Section 01 00 00, GENERAL REQUIREMENTS.
3.3 INSTRUCTIONS
Provide services of manufacturer’s technical representative for four
hours to instruct VA personnel in operation and maintenance of heat
pumps.
3.4 STARTUP AND TESTING
A. The Commissioning Agent will observe startup and contractor testing of
selected equipment. Coordinate the startup and contractor testing
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schedules with the Resident Engineer and Commissioning Agent. Provide a
minimum of 7 days prior notice.
3.5 COMMISSIONING
A. Provide commissioning documentation in accordance with the requirements
of Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS for all inspection,
start up, and contractor testing required above and required by the
System Readiness Checklist provided by the Commissioning Agent.
B. Components provided under this section of the specification will be
tested as part of a larger system. Refer to Section 23 08 00 –
COMMISSIONING OF HVAC SYSTEMS and related sections for contractor
responsibilities for system commissioning.
3.6 DEMONSTRATION AND TRAINING
A. Provide services of manufacturer’s technical representative for four
hours to instruct VA personnel in operation and maintenance of units.
B. Submit training plans and instructor qualifications in accordance with
the requirements of Section 23 08 00 – COMMISSIONING OF HVAC SYSTEMS.
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